Dennis Allen used to be a defensive backs coach, so maybe he is just picky. But the Raiders head coach is on his third set of starting cornerbacks in his three years. This season, general manager Reggie McKenzie and Allen didn't look far, just across the bridge, for a solution.

Oakland brought in Tarell Brown and Carlos Rogers, who played together for three years for the 49ers. The Raiders hope they remember something about winning, as San Francisco was 36-11 over that span when they both were in the lineup.

"The one thing that really jumps off the table at me about both those guys is their understanding of the game and their professionalism," Allen said. "I think that's a big key to why they've been able to be successful. They do a good job of studying tape and understanding what an offense is trying to do to them and can keep themselves from getting in bad positions."

Brown and Rogers also do a great job of communicating with each other.

"It definitely helps playing with someone you've been around for a few years," Brown said. "Communication level, knowing his body language, he knows mine. It definitely makes it a lot easier."

Brown, 29, signed a one-year deal for $3.5 million. He had a sense the writing was on the wall when the 49ers signed Tramaine Brock.

The Raiders, meanwhile, just wanted to get better, after not being excited about how starters Ron Bartell and Shawntae Spencer looked in 2012, or Mike Jenkins and Tracy Porter last season. Jenkins signed with the Bucs and Porter with Washington, while Spencer and Bartell are out of the NFL.

The Raiders had a good source of information on Brown and Rogers, because defensive coordinator Jason Tarver was a defensive ends coach on the 49ers when Brown showed up on the scene. He left for Stanford when Rogers arrived, but Tarver's scheme has a lot of 49ers roots.

He said both players picked things up quickly at training camp.

While Brown downplays his role mentoring the younger players - "I just talk a lot of trash" - Tarver said he has emulated the older Rogers in giving out pointers.

"He does a great job communicating with our younger players," Tarver said. "He had some good discussions with some of our linebackers today about what they're trying to do to him. So, he's really become a professional. He wants to be the best in the world and that's what we all want to be, we want to be the best in the world. That's why I'm glad he's here."

Brown said he has learned a lot since he met Tarver.

"I was a young buck when I first came in, just playing off of raw talent," he said.

Rogers, who moved outside from the slot when second-year corner DJ Hayden was injured again, sees a lot of similarities between the old 49ers and this edition of the Raiders.

"A team that brought me in to help change things around," Rogers said. "Hopefully I can bring that same attitude, that intensity, that same work ethic and we can get this thing changed around."